title: Bioreduction of para-chloronitrobenzene in a hydrogen-based hollow-fiber membrane biofilm reactor: effects of nitrate and sulfate.
abstract: A continuous-stirred, hydrogen-based, hollow-fiber membrane biofilm reactor (HFMBfR) that was active in nitrate and sulfate reductions was shown to be effective for degradation or detoxification of para-chloronitrobenzene (p-CNB) in water by biotransforming it first to para-chloroaniline (nitro-reduction) and then to aniline (reductive dechlorination) with hydrogen (H2) as an electron donor. A series of short-term experiments examined the effects of nitrate and sulfate on p-CNB bioreduction. The results obtained showed both higher nitrate and sulfate concentration declined the p-CNB bioreduction in the biofilm, and this suggests the competition for H2 caused less H2 available for the p-CNB bioreduction when the H2 demand for the reductions was larger. Denitrification and sulfate reduction intermediates were thought to be potential factors inhibiting the p-CNB bioreduction. Analysis of electron-equivalent fluxes and reaction orders in the biofilm further demonstrated both denitrification and sulfate reduction competed more strongly for H2 availability than p-CNB bioreduction. These findings have significant implications for the HFMBfR used for degrading p-CNB under denitrifying and/or sulfate reducing conditions.
authors.affiliation: Guangxi Key Laboratory of Environmental Pollution Control Theory and Technology, College of Environmental Science and Engineering, Guilin University of Technology, 12# Jiangan Road, Guilin, 541004, Guangxi, China.
authors.forename: Haixiang
authors.initials: H
authors.lastname: Li
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xiaoyin
authors.initials: X
authors.lastname: Xu
authors.forename: Jun
authors.initials: J
authors.lastname: Liang
authors.forename: Siqing
authors.initials: S
authors.lastname: Xia
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001554:Benzene / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018441:Biofilms; D019149:Bioreactors / Q000382:microbiology*; D058440:Denitrification; D052918:Environmental Restoration and Remediation / Q000295:instrumentation / Q000379:methods*; D006859:Hydrogen / Q000378:metabolism*; D009566:Nitrates / Q000378:metabolism*; D009574:Nitro Compounds / Q000378:metabolism*; D010084:Oxidation-Reduction; D013431:Sulfates / Q000378:metabolism*
chemical_list: D009566:Nitrates; D009574:Nitro Compounds; D013431:Sulfates; D006859:Hydrogen; D001554:Benzene